Data transmission device

ABSTRACT

The device relates to an installation comprising a cavity extending from the surface of the ground and provided with at least one electrically conductive tubular element. The device comprises a single-strand smooth cable for supporting an action and/or measurement assembly, which cable is electrically conductive and has a breaking strength greater than 300 daN, and is disposed in the tubular element. The surface of the cable is electrically insulated at least in part from said tubular element. The device includes transmitter means and receiver means for transmitting and receiving an electrical and/or electromagnetic signal, said means being situated in the vicinity of the surface and in the cavity, and being electrically connected to the cable and to the tubular element and/or an underground formation. The invention is applicable to transmitting information and to controlling tools in an oil well.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device for transmitting data in aninstallation for working fluids contained underground, the installationcomprising a cavity defined in an underground formation and extendingfrom the surface of the ground. The cavity is provided with at least oneelectrically conductive tubular element, and the device is of a typecomprising a single-strand smooth cable for supporting an action and/ormeasurement assembly. The cable has a breaking strength greater than 300decanewtons (daN), and is made of an electrically conductive materialand disposed in the tubular element between a first point at the surfaceof the ground and a second point within the cavity. The invention alsorelates to an associated installation for working fluids containedunderground.

The term “tubular element” is used to designate an element that ishollow and elongated, for example an element that is substantiallycylindrical.

2. Description of Related Art

It is known to use single-strand smooth cables of the “piano wire” or“slickline” type to perform various mechanical operations (commonlyreferred to as “cable operations” or “slickline operations”) down an oilwell or a well for some other effluent (in particular gas, steam,water). By way of example, such operations may be opening and closingvalves, putting elements into place, or perforating a wall.

These cables which are referred to as “smooth cables” or “piano wire” inthe present application, present the advantage of being simple to use.By their very nature they possess good mechanical properties, unliketwisted electrical cables. Providing sealing at the wellhead issignificantly easier with “piano wire” type cables than it is withtwisted electrical cables.

Nevertheless, use of such cables is limited to a mechanical function,and that can present drawbacks. For example, with perforationoperations, when an explosive charge is lowered down a well at the endof a piano wire type cable, a timer is provided to trigger the explosiveat the end of a predetermined length of time. Under such circumstances,an operator at the surface has no way of being sure that the explosionhas indeed taken place, and when the cable is raised back to thesurface, the tool may contain undetonated residual explosive, which canbe dangerous.

Twisted electrical cables are also known that enable transmission ofelectrical signals. Nevertheless, such cables are more expensive, andhandling them at a wellhead is more complicated than handling a smoothcable.

BRIEF SUMMARY OF THE INVENTION

A main object of the present invention is to provide means that areparticularly simple and inexpensive for transmitting data between acontrol device on the surface and a tool located at the end of a pianowire type cable, or between measurement means situated in the well andthe surface.

To this end, the invention provides a device of the above-specifiedtype, characterized in that the surface of the cable is electricallyinsulated, at least in part, from said tubular element, and in that thedevice further comprises transmitter means for transmitting anelectrical and/or electromagnetic signal, situated in the vicinity ofone or both of the first and second points, and receiver means forreceiving an electrical and/or electromagnetic signal situated in thevicinity of the other one or both of the first and second points; eachof said transmitter means and said receiver means being electricallyconnected firstly to the cable and secondly to the tubular elementand/or to the underground formation; the cable constituting a portion ofa loop for conveying the electrical and/or electromagnetic signalbetween the transmitter means and the receiver means.

The device of the invention may include one or more of the followingcharacteristics taken alone or in any technically feasible combination:

-   -   the surface of the cable carries a continuous coating of        insulating material and is electrically insulated from said        tubular element;    -   the thickness of the continuous coating of insulating material        is equal to half the difference in diameter between two standard        and non-coated cables;    -   the surface of the cable is provided at regular intervals with        centralizers of insulating material for electrically insulating        said tubular element;    -   the transmitter and receiver means in the vicinity of the first        and second points are electrically connected to said tubular        element and the signal transmitted by the transmitter means and        received by the receiver means is an electrical signal;    -   the cavity is provided with at least a first tubular element and        a second tubular element disposed inside the first element, and        the cable is disposed in the annular space between the first and        second elements;    -   the surface of the cable has at least one electrical contact        point with said tubular element, and the transmitter means        and/or receiver means in the vicinity of the first and second        points and said tubular element are electrically connected to        the underground formation;    -   the electrical signal transmitted by the transmitter means in        the vicinity of the first point is injected to a first dipole        comprising firstly an electrical contact point between the cable        and the transmitter means in the vicinity of the first point,        and secondly an electrical contact point between the formation        and the transmitter means in the vicinity of the first point;        the first dipole generating an electromagnetic signal that is        received by a second dipole comprising firstly one of said        electrical contact points between the cable and the tubular        element, and secondly an electrical contact point between the        tubular element and the receiver means in the vicinity of the        second point, with the electromagnetic signal received by the        second dipole generating an electrical signal which is conveyed        to the receiver means in the vicinity of the second point;    -   the electrical signal transmitted by the transmitter means in        the vicinity of the second point is injected into a second        dipole comprising firstly one of said electrical contact points        between the cable and the tubular element, and secondly an        electrical contact point between the tubular element and the        transmitter means in the vicinity of the second point, said        second dipole generating an electromagnetic signal received by a        first dipole comprising, firstly an electrical contact point        between the cable and the receiver means in the vicinity of the        first point, and secondly an electrical contact point between        the formation and the receiver means in the vicinity of the        first point; the electromagnetic signal received by the first        dipole generating an electrical signal that is conveyed to the        receiver means in the vicinity of the first point;    -   the electrical contact between the underground formation and the        transmitter and/or receiver means in the vicinity of the first        point takes place via a conductor member anchored in the ground;    -   the transmitter means and the receiver means for transmitting        and receiving an electrical and/or an electromagnetic signal are        situated in the vicinity of respective ones of the first and        second points; and    -   the transmitter means for transmitting an electrical and/or an        electromagnetic signal are situated solely in the vicinity of        one of the first and second points, and the receiver means for        receiving an electrical and/or an electromagnetic signal are        situated solely in the vicinity of the other one of the first        and second points.

The invention also provides an installation for working fluids containedunderground, the installation comprising a cavity defined in anunderground formation extending from the surface of the ground andclosed on the surface by a wellhead, said cavity being provided with atleast one electrically conductive tubular element, characterized in thatit includes a transmission device as defined above.

The installation of the invention may include one or more of thefollowing characteristics taken alone or in any technically feasiblecombination:

-   -   it includes an applicator device for applying an insulating        coating on the cable;    -   the wellhead is preceded by an airlock provided with a sealing        device for the cable, and the applicator device for applying the        insulating coating on the cable is disposed inside the airlock        downstream from the sealing device; and    -   it includes deployment means and an alignment device for putting        the cable into alignment in the wellhead, the alignment device        comprising at least one sheath, the installation being        characterized in that the applicator device for applying the        insulating coating on the cable is disposed between the        deployment means and the alignment device, and the or each        sheath is electrically insulated from the wellhead and/or the        underground formation.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described below with reference to theaccompanying drawings, in which:

FIG. 1 is a diagram of a first configuration of a transmission device ofthe invention;

FIG. 2 is a diagram of a device for in situ application of an insulatingcoating on the surface of the cable of the piano wire type;

FIG. 3 is a diagram of a second configuration of a transmission deviceof the invention; and

FIG. 4 is a diagram of a third configuration of a transmission device ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

A device of the invention is used, for example, when taking action in anoil production well installation 1, such as taking measurements down theborehole or a perforation operation implemented by means of a toolmounted at the end of a cable of the piano wire type.

The device comprises a smooth cable 3 supporting an assembly 5 fortaking action and/or measurements, and associated with deployment means7. The device further comprises first means 9 and second means 11 fortransmitting/receiving an electrical and/or electromagnetic signal.

The oil production well installation 1 has a cavity 13 or “well” closedby a wellhead 15 on the surface of the ground 17.

This cavity 13 is generally tubular in shape. It extends from thesurface of the ground 17 to the layer of fluid to be worked (not shown)situated at depth in a subsurface formation 19. It is defined by anouter first tubular duct 21 referred to as “casing”, made up of anassembly of tubes made of electrically conductive material (metal).

A second tubular duct 25 (referred to as “production tubing”) of smallerdiameter is mounted inside the first duct 21 and is likewise constitutedby an assembly of metal tubes. The second duct 25 is held substantiallyin the center of the first duct 21 by means of bladed centralizers 27made of electrically conductive material (metal).

The wellhead 15 comprises a body 31 of electrically conductive materialand is provided with a servicing valve 33.

The body 31 of the wellhead 15 is mounted at the end of the first duct21 at the surface of the ground 17. The end of the second duct 25 ismounted inside the body 31. The second duct 25 is closed by theservicing valve 33 which is situated in line with the second duct 25.

The smooth cable 3 is a single-strand cable of the piano wire type or ofthe slickline type. It is made of a metal, such as galvanized steel orstainless steel (e.g. of the 316 type). The smooth cable possesses goodtraction strength and adequate flexibility. Typically, this type ofcable has a breaking load in the range 300 daN to 1500 daN, andpreferably in the range 600 daN to 1000 daN, and relatively highelectrical resistivity, typically lying in the range 30 milliohms permeter (mΩ/m) to 500 mΩ/m, and preferably lying in the range 35 mΩ/m to300 mΩ/m.

The diameter of the smooth cable 3 is adapted for insertion into thewellhead 15. Typically the diameter of cables of this type lies in therange 1 millimeter (mm) to 5 mm, and preferably in the range 1.5 mm to 4mm.

The smooth cable 3 is inserted into the second duct 25 by the deploymentmeans 7. These means 7 comprise a winch 41 provided with a drum 42associated with a hydraulic or electrical unit 43 and an alignment andsealing device 45.

The deployment means 7 for deploying the smooth cable 3 may be placed onthe ground 17 or possibly they may be on board a vehicle (not shown).

The first end of the smooth cable 3 is secured to the drum 42. Thealignment and sealing device 45 comprises two deflector pulleys 49, anairlock 51, and a packer 53.

Since the outside surface of the cable 3 is smooth, sealing through theairlock 51 can be achieved using a simple packer 53.

The smooth cable 3 carries an action and/or measurement assembly 5 atits free end, comprising, under such circumstances, an active portion55, in particular a tool, together with a control portion 57.

The tool 55 enables one or more operations to be performed in the well.These operations are controlled from the surface of the ground 17 usingthe data transmission device of the invention.

In the first embodiment (FIG. 1), the outside surface of the smoothcable 3 is completely insulated electrically from the second duct 25. Todo this, an electrically insulating material is applied to the outsidesurface of the smooth cable 3.

This continuous insulating material may be selected from a thermoplasticmaterial, a paint, or a resin, and it may be applied in a permanentmanner on the cable. It may also be applied in a temporary manner, inwhich case it is selected from amongst greases, lubricants, tars, andanalogous substances.

The insulating material may be applied onto the smooth cable 3 while thecable 3 is being drawn or conditioned. This application may also beperformed off-site, in the vicinity of the cavity 13, by means of anapplicator device 61 described with reference to FIG. 2.

The applicator device may be interposed in the airlock 51 between itsend 53 and the servicing valve 33 of the wellhead. It comprises achamber 63 for applying an insulating substance injected through a valve65, and means 67 for heating, melting, or curing the substance, forexample induction heater turns.

If the applicator device 61 is placed in the airlock 51, the deflectorpulley 49 and the drum 42 need to be electrically insulated from thewellhead and/or the formation 19 so as to ensure that the transmissiondevice of the invention operates properly.

In a variant, the applicator device 61 may alternatively be placedbetween the winch 41 and the bottom deflector pulley 49.

Advantageously, it is possible to use a standard smooth cable 3 that isnot coated (e.g. having a diameter of 2.34 mm or of 2.74 mm) and toapply on the smooth cable 3 a coating of thickness equal to half thedifference in diameter between said cable 3 and a standard smooth cableof larger diameter. Thus, the smooth cable 3 once coated is of astandard size for existing “slickline” equipment (2.74 mm or 3.17 mm inthe above example). The coated smooth cable 3 then adapts easily toexisting slickline equipment.

In a variant of the invention that is not shown, the smooth cable 3 maybe electrically insulated from the second duct by means of centralizers71 of insulating material disposed at regular intervals along the secondduct 25, without using an insulating coating.

First transceiver means 9 for transmitting and receiving an electricalsignal is disposed in the vicinity of the wellhead 15. It comprises acontrol unit 73 that is electrically connected both to the smooth cable3 and to the wellhead 15.

Second transceiver means 11 for transmitting and receiving an electricalsignal are mounted at the second end of the smooth cable 3 in thevicinity of the tool 55. The second transceiver means 11 is connected tothe control portion 57. In this first transmission device of theinvention, this means 11 is also electrically connected firstly to thesmooth cable 3 and secondly to the second duct 25.

Each of the first and second transceiver means comprises an electroniccircuit and a power supply, e.g. a battery. These means are capable oftransmitting and receiving a modulated alternating electrical signal atlow or medium frequency. Such means are known in themselves and are notdescribed in detail. An example of a transceiver suitable for use in thedevice is made available by the supplier Geoservices under the name WTD(wireless transmitted data).

The term low or medium frequency covers frequencies in the range 1 hertz(Hz) to 50,000 Hz, and preferably in the range 5 Hz to 5000 Hz. Datatransmission between the transmitter means and the receiver means takesplace over distances lying in the range 0 to 10,000 meters (m), andpreferably over the range 500 m to 6000 m.

The electrical signal transmitted from the surface downhole is, undersuch circumstances, a control signal generated by the operator, whilethe electrical signal transmitted from down the hole to the surface is aconfirmation signal generated by the control portion 57.

The current injected by the transmitter means 9, 11 lies in the range 0to 10 amps (A), preferably in the range 0 to 2 A, at a voltage lying inthe range 0 to 50 volts (V), and preferably in the range 5 V to 25 V.These means are identical to those commonly used in the context oftransmitting data by means of an electromagnetic signal.

In a variant, a current source of the kind used for transmitting signalsover a twisted electrical cable could be used in this first embodiment.An example of a current source suitable for this use is made availableby the supplier Geoservices under the name Emrod® shuttle.

Furthermore, when it is necessary only to transmit from the surface downthe well, e.g. merely to issue a command, the operator on the surfaceactuates a simple transmitter means 9 and the action and/or measurementassembly 5 need be provided solely with receiver means 11.

In another variant, the action and/or measurement assembly 5 may alsoinclude means (not shown) for detecting physical quantities, such astemperature, pressure, flow rate, depth, status of a downhole valve,natural radiation from the terrain (gamma radiation), location of casingseals “Casing Collar Locator”, etc.

When merely performing measurements downhole, the action and/ormeasurement assembly 5 may comprise solely detector means and atransmitter means 11, in which case the surface is fitted solely withreceiver means 9.

The operation of the first device of the invention during a perforationoperation is described below by way of example.

When the action and/or measurement assembly 5 has reached the desireddepth, the first transceiver means 9 at the surface of the ground 17sends an electrical control signal in the form of a modulated electricalcurrent. Since the smooth cable 3 is electrically insulated from thesecond duct 25, a current loop is established between the firsttransceiver means 9, the smooth cable 3, the second transceiver means11, the second duct 25, and the wellhead 15. In spite of the poorelectrical conductivity properties of the cable 3, the electricalcontrol signal is conveyed to the control member 57 of the action and/ormeasurement assembly 5 via the cable 3. The active portion 55 of theaction and/or measurement assembly 5 then performs the command, forexample it triggers an explosive charge.

When the active portion 55 of the action and/or measurement assembly 5has finished executing a command, the second transceiver means 11 sendsan electrical confirmation signal in the form of an electrical currentthat flows around the above-described current loop. This confirmationsignal is received by the first transceiver means 9. An operator on thesurface can thus receive confirmation that the commanded operation hasbeen performed properly and can move on to the following operation (e.g.raising the cable together with the action and/or measurement assembly).

A second data transmission device of the invention is shown in FIG. 3.

Unlike the first device of the invention, the smooth cable 3 is placedin the annular space between the first duct 21 and the second duct 25.

This smooth cable 3 is installed permanently in the oil production wellinstallation shown in FIG. 3. For this purpose, the smooth cable 3 maybe secured to the outside surface of the second duct 25 by fasteners 75that are put into position while the second duct 25 is itself being putinto place inside the first duct 21.

In this second device of the invention, the outside surface of thesmooth cable 3 is coated in an insulating material that is applied on apermanent basis.

Unlike the installation shown in FIG. 1, the deployment means 7 are nolonger necessary. The smooth cable is thus connected directly to thecontrol unit 73.

The operation of the second device of the invention is otherwiseidentical to that of the first device of the invention.

A third data transmission device of the invention is shown in FIG. 4.

Unlike the device shown in FIG. 1, the surface of the smooth cable 3 hasat least one point 81 of electrical contact with the second duct 25.

Furthermore, the first transceiver means 9 are connected electricallyfirstly to the smooth cable 3 and secondly to the subsurface formation19 via a stake 83 of electrically conductive material that is plungedinto the formation 19 at the surface of the ground 17.

In a variant, the stake 83 may be plunged into a seabed, if theinstallation relates to an off-shore borehole.

The operation of the third device of the invention is analogous to thatof the first device of the invention.

Once the action and/or measurement assembly 5 has been positioned at thedesired depth, the first transceiver means 9 transmit an electricalcontrol signal. This signal is identical to that generated in the firstdevice of the invention. It may therefore be generated by means that areidentical.

This signal is injected into a first dipole formed firstly by thecontact point 84 between the cable 3 and the first transceiver means,and secondly the stake 83. The electrical signal injected into thisfirst dipole causes an electromagnetic control signal to propagatethrough the surrounding terrain, specifically an electromagnetic wavewhich contains the information that is to be transmitted. Thiselectromagnetic control signal then moves down towards the bottom of thewell, being guided by the smooth cable 3 and/or the second duct 25. Theelectromagnetic control signal is picked up by a second dipole formedfirstly by the electrical contact point 81 of the cable 3 with thesecond duct 25 that is closest to the action and/or measurement assembly5, and secondly the electrical contact point 87 between the secondtransceiver means 9 and the second duct 25, the second duct beingelectrically connected to the formation 19 by the centralizers 27 andthe first duct 21. The electromagnetic signal received by the seconddipole generates an electrical signal which is received by the secondtransceiver means 11.

Similarly, the confirmation signal from the action and/or measurementassembly 5 is generated in the form of an electrical signal injectedinto a first dipole formed firstly by the electrical contact point 81between the cable 3 and the second duct 25 that is closest to the actionand/or measurement assembly 5, and secondly the electrical contact point87 between the transmitter means 11 and the second duct 25. This contactpoint is electrically connected to the formation 19. The electricalsignal injected into the first dipole causes an electromagnetic controlsignal to propagate through the terrain surrounding the well,specifically an electromagnetic wave which contains the information tobe conveyed. This electromagnetic confirmation signal then rises to thesurface, being guided by the smooth cable 3 and/or the second duct 25.The electromagnetic confirmation signal is picked up by a second dipoleformed between firstly the electrical contact point 84 between the firsttransceiver means 9 and the cable 3, and secondly the electrical contactpoint between the first transceiver means 9 and the formation 19 via thestake 83. The electromagnetic signal received by the second dipolegenerates an electrical signal which is received by the firsttransceiver means 9.

By means of the invention as described above, a device is obtained fortransmitting data in real time between a tool situated at the end of asingle-strand smooth cable of the “piano wire” type that is located downan oil production well installation, and a control member on thesurface.

It is thus possible to take advantage simultaneously firstly of themechanical properties of smooth cables for performing “slickline”operations, namely ease of providing sealing at the wellhead and highmechanical strength compared with twisted electrical cables, andsecondly of the possibility of transmitting information in real timebetween the surface and a point downhole. This result is obtainedsurprisingly, in spite of the poor electrical conductivity properties ofthe smooth cable.

Furthermore, the device can easily be adapted to an existinginstallation.

1. A transmission device for transmitting data in an installation forworking fluids contained underground, the installation comprising acavity defined in an underground formation and extending to the surfaceof the ground, and at least one electrically conductive tubular elementhaving a first point at the surface of the ground and a second pointwithin the cavity, the transmission device comprising: a single-strandsmooth cable for supporting an action and/or measurement assembly, saidcable having a breaking strength greater than 300 daN, being made of anelectrically conductive material, and being disposed in the tubularelement between the first point and the second point, wherein a surfaceof said cable is electrically insulated, at least in part, from thetubular element; transmitter means for transmitting an electrical and/orelectromagnetic signal, said transmitter means being situated in avicinity of one or both of the first point and the second point, saidtransmitter means having: a first electrical contact point with thetubular element; and a second electrical contact point with said cable,said second electrical contact point of said transmitter means beingelectrically separated from said first electrical contact point of saidtransmitter means such that said transmitter means can apply a voltagebetween said first electrical contact point of said transmitter meansand said second electrical contact point of said transmitter means; andreceiver means for receiving the electrical and/or electromagneticsignal, said receiver means being situated in a vicinity of the otherone or both of the first point and the second point, said receiver meanshaving: a first electrical contact point with the tubular element; and asecond electrical contact point with said cable, said second electricalcontact point of said receiver means being electrically separated fromsaid first electrical contact point of said receiver means such thatsaid receiver means can detect a voltage between said first electricalcontact point of said receiver means and said second electrical contactpoint of said receiver means, wherein said cable is a portion of a loopfor conveying the electrical and/or electromagnetic signal between saidtransmitter means and said receiver means.
 2. A transmission deviceaccording to claim 1, wherein said surface of said cable carries acontinuous coating of insulating material and is electrically insulatedfrom the tubular element.
 3. A transmission device according to claim 2,wherein a thickness of said continuous coating of insulating material isequal to half the difference in diameter between two standard andnon-coated cables.
 4. A transmission device according to claim 1,wherein said surface of said cable is provided at regular intervals withcentralizers of insulating material for electrically insulating saidcable from the tubular element.
 5. A transmission device according toclaim 1, wherein said transmitter means and said receiver means areelectrically connected to the at least one electrically conductivetubular element, wherein said surface of said cable carries a continuouscoating of insulating material and is completely electrically insulatedfrom the at least one electrically conductive tubular element, andwherein the electrical and/or electromagnetic signal transmitted by saidtransmitter means and received by said receiver means is an electricalsignal.
 6. A transmission device according to claim 1, wherein the atleast one electrically conductive tubular element is at least a firsttubular element and a second tubular element disposed inside said firsttubular element, and wherein said cable is disposed in an annular spacebetween said first tubular element and said second tubular element.
 7. Atransmission device according to claim 1, wherein the surface of thecable has at least one electrical contact point with the at least oneelectrically conductive tubular element, and wherein said transmittermeans and/or said receiver means, and the at least one electricallyconductive tubular element are electrically connected to the undergroundformation.
 8. A transmission device according to claim 1, furthercomprising a conductor member anchored in the ground, wherein saidconductor member electrically connects said transmitter means and/orsaid receiver means, in the vicinity of the first point, to theunderground formation.
 9. A transmission device according to claim 1,wherein said transmitter means and said receiver means are situated inthe vicinity of the first point and the second point, respectively. 10.A transmission device according to claim 1, wherein said transmittermeans is situated solely in a vicinity of one of the first point and thesecond point, and said receiver means is situated solely in a vicinityof the other one of the first point and the second point.
 11. Aninstallation for working fluids contained underground, the installationcomprising: a cavity defined in an underground formation extending tothe surface of the ground and closed on the surface by a wellhead; atleast one electrically conductive tubular element provided in saidcavity; and a transmission device according to claim
 1. 12. Aninstallation according to claim 11, further comprising an applicatordevice for applying an insulating coating on said cable.
 13. Aninstallation according to claim 12, wherein said applicator device isdisposed inside an airlock preceding the wellhead, the airlock includinga sealing device for said cable, said applicator device being locateddownstream from the sealing device.
 14. An installation according toclaim 12, further comprising: deployment means for deploying said cable;and an alignment device for aligning said cable in the wellhead, saidalignment device comprising at least one pulley, each pulley beingelectrically insulated from the wellhead and/or the undergroundformation, wherein said applicator device is disposed between saiddeployment means and said alignment device.
 15. A transmission deviceaccording to claim 1, wherein said cable has a resistivity that isgreater than 30 mΩ/m.
 16. A transmission device according to claim 1,wherein said cable is a slickline cable or a “piano wire” cable.
 17. Atransmission device according to claim 1, wherein said second electricalcontact point of at least one of said transmitter means and saidreceiver means is located outside of the cavity in the vicinity of thefirst point.
 18. A transmission device according to claim 1, whereineach of at least one of said transmitter means and said receiver meansin a vicinity of the first point are connected to said cable through afirst electrical line and connected to the tubular element through asecond electrical line different from the first electrical line.
 19. Atransmission device for transmitting data in an installation for workingfluids contained underground, the installation comprising a cavitydefined in an underground formation and extending to the surface of theground, and at least one electrically conductive tubular element havinga first point at the surface of the ground and a second point within thecavity, the transmission device comprising: a single-strand smooth cablefor supporting an action and/or measurement assembly, said cable havinga breaking strength greater than 300 daN, being made of an electricallyconductive material, and being disposed in the tubular element betweenthe first point and the second point, wherein a surface of said cable iselectrically insulated, at least in part, from the tubular element;transmitter means for transmitting an electrical and/or electromagneticsignal, said transmitter means being electrically connected to saidcable and to the tubular element and/or the underground formation, andbeing situated in a vicinity of the first point; and receiver means forreceiving the electrical and/or electromagnetic signal, said receivermeans being electrically connected to said cable and to the tubularelement and/or the underground formation, and being situated in avicinity of the second point, wherein said cable is a portion of a loopfor conveying the electrical and/or electromagnetic signal between saidtransmitter means and said receiver means, wherein said surface of saidcable has at least one electrical contact point with the at least oneelectrically conductive tubular element, wherein said transmitter meansand/or said receiver means, and the at least one electrically conductivetubular element are electrically connected to the underground formation,wherein the electrical and/or electromagnetic signal transmitted by saidtransmitter means is injected to a first dipole comprising an electricalcontact point between said cable and said transmitter means, and anelectrical contact point between the underground formation and saidtransmitter means, wherein the first dipole generates an electromagneticsignal that is received by a second dipole comprising one of saidelectrical contact points between said cable and the at least oneelectrically conductive tubular element, and an electrical contact pointbetween the at least one electrically conductive tubular element andsaid receiver means, and wherein the second dipole generates anelectrical signal which is conveyed to said receiver means.
 20. Atransmission device for transmitting data in an installation for workingfluids contained underground, the installation comprising a cavitydefined in an underground formation and extending to the surface of theground, and at least one electrically conductive tubular element havinga first point at the surface of the ground and a second point within thecavity, the transmission device comprising: a single-strand smooth cablefor supporting an action and/or measurement assembly, said cable havinga breaking strength greater than 300 daN, being made of an electricallyconductive material, and being disposed in the tubular element betweenthe first point and the second point, wherein a surface of said cable iselectrically insulated, at least in part, from the tubular element;transmitter means for transmitting an electrical and/or electromagneticsignal, said transmitter means being electrically connected to saidcable and to the tubular element and/or the underground formation, andbeing situated in a vicinity of the second point; and receiver means forreceiving the electrical and/or electromagnetic signal, said receivermeans being electrically connected to said cable and to the tubularelement and/or the underground formation, and being situated in avicinity of the first point, wherein said cable is a portion of a loopfor conveying the electrical and/or electromagnetic signal between saidtransmitter means and said receiver means, wherein said surface of saidcable has at least one electrical contact point with the at least oneelectrically conductive tubular element, wherein said transmitter meansand/or said receiver means, and the at least one electrically conductivetubular element are electrically connected to the underground formation,wherein the electrical and/or electromagnetic signal transmitted by saidtransmitter means is injected into a second dipole comprising one ofsaid electrical contact points between said cable and the at least oneelectrically conductive tubular element, and an electrical contact pointbetween the at least one electrically conductive tubular element andsaid transmitter means, wherein the second dipole generates anelectromagnetic signal received by a first dipole comprising anelectrical contact point between said cable and said receiver means andan electrical contact point between the underground formation and saidreceiver means, and wherein the first dipole generates an electricalsignal that is conveyed to said receiver means.